Adhesives: What is Epoxy?

Epoxy comes in three main types: paint, plastic, and adhesive. These types are all made from polymers that contain epoxides (hence the name “epoxy”). The paint type is used in flooring and coating metal tools and parts to protect them from scuffs, rust, and corrosion. Plastics made from epoxy are strong, resist heat, resist corrosion, and don’t conduct electricity. Epoxy adhesives are particularly useful to the DIY’er, as they can form very strong, solid bonds between different materials. They are also fast-drying and resist water and solvents. Epoxies come in many different formulations for use in bonding different substances. Here are a few of the things to look for when choosing an adhesive for a project.

Will your project involve very high or low temperatures?

Epoxies come in a variety of temperature ranges. Some epoxies will melt or break down if they get too hot. Most epoxies become brittle when it’s very cold. There are special types of epoxy glue that are resistant to extreme temperatures. If you are gluing together two objects that will be stored in a hot area, or if one of them generates heat, be sure to check the temperature range of the epoxy to make sure it will hold up. The same holds true if you will be storing the glued object outside in the cold. Err on the side of caution when selecting an epoxy adhesive. Unless you intend to expose it to extreme heat or cold, pick one with as wide a temperature range as possible. If you are going to expose the object you are epoxying to extreme heat or cold, select an epoxy that has plenty of heat or cold resistance to hold up to it. Epoxies usually have their temperature ranges listed on their package.

What materials are you trying to put together?

Epoxies also come in different formulas for bonding different types of materials. Some can bond plastic, rubber, and wood, but not metal. Make sure that you check the list of materials listed on the packaging to be sure that the epoxy you buy will bond to both objects you’re gluing together. Some epoxies cure hard enough that you can drill or sand them. These are very useful for woodworking.

How to use epoxy

Most epoxy adhesives come in two separate tubes that must be mixed before using.

Most epoxies come in two tubes. The adhesive itself is created when you mix the two different epoxies together. Once you mix them, you must apply them right away because they dry and cure very quickly. Most epoxies dry and cure in under five minutes, and some formulations only take a minute to dry. All you need to do is clean the surfaces you will be joining, mix the two epoxy components together on a paper plate apply with a toothpick for finer projects, and with a popsicle stick, plastic spoon or knife, or other disposable tool for larger applications. Join the pieces together after applying epoxy to both and hold them for the time suggested for the epoxy you choose. After the short wait, you will have a strong, water-resistant bond that should last for years.